1. Field of the Invention
The present invention relates to a method of producing a glassy alloy, and particularly to a technique capable of obtaining a glassy alloy having a thickness significantly larger than conventional amorphous alloy ribbons, excellent magnetic properties and high resistivity.
2. Description of the Related Art
Some of conventional multi-element alloys are known to have a wide temperature region in a supercooled liquid state before crystallization, and constitute glassy alloys. Such glassy alloys are also known to become bulk-shaped alloys significantly thicker than amorphous alloy ribbons produced by a conventional known melt quenching method.
Examples of such conventional known glassy alloys include alloys having the compositions of Ln--Al--TM, Mg--Ln--TM, Zr--Al--TM, Hf--Al--TM, Ti--Zr--Be--TM (wherein Ln indicates a rare earth element, and TM indicates a transition metal), and the like.
However, all these conventional known glassy alloys have no magnetism at room temperature, and from this viewpoint, such glassy alloys have a large industrial limit when considered as magnetic materials.
Therefore, research and development have conventionally progressed for obtaining an amorphous alloy which has magnetism at room temperature and which can be obtained in a thick bulk shape.
Although alloys having various compositions exhibit a supercooled liquid region, the temperature width .DELTA.T.sub.x of the supercooled liquid region, i.e., the difference between the crystallization temperature (T.sub.x) and the glass transition temperature (T.sub.g), i.e., the value of (T.sub.x -T.sub.g), is generally small, and these alloys have the low ability to form an amorphous phase and are thus impractical. Considering this property, an alloy which has a wide supercooled liquid temperature region, and which can form a glassy alloy by cooling can overcome a limit to the thickness of a conventional known amorphous alloy ribbon, and thus the alloy should attract much attention from a metallurgical stand point. However, whether such an alloy can be developed as an industrial material depends upon discovery of an amorphous alloy exhibiting ferromagnetism at room temperature.
In consideration of the above background, the inventors previously found a glassy alloy having ferromagnetism at room temperature, and filed application for a patent in the specification of Japanese Patent Application No. 8-243756. However, as a result of repetitions of research on a method of producing such a glassy alloy exhibiting ferromagnetism at room temperature, the inventors achieved the present invention.